Start with the amount actually borrowed
Subtract the down payment from the home price to obtain the loan principal. These are distinct inputs: the home price is not automatically the debt.
The down payment must be smaller than the home price in this mortgage model. A fully cash-funded purchase does not need a loan-payment calculation.
Add annual costs on a monthly basis
The loan formula estimates principal and interest using a fixed rate and regular monthly payments. Divide annual property tax and annual home insurance by 12 before adding them.
Those monthly amounts are budget estimates. Actual escrow requirements, billing timing and adjustments may differ. Entering a monthly tax amount into an annual field understates the estimate by a factor of twelve.
Keep excluded costs visible
PMI, HOA dues, closing costs, maintenance and future changes in tax, insurance or interest rates are not included. Blank optional down-payment, tax and insurance fields are treated as zero.
The output is an arithmetic estimate, not a lender quote, approval or affordability decision. Compare your actual loan terms and recurring charges separately before using the total in a budget.
LET’S WORK IT THROUGH
A modeled loan payment is 900 per month, annual tax is 2,400 and annual insurance is 600. Find the combined monthly estimate.
- Property tax per month: 2,400 ÷ 12 = 200.
- Insurance per month: 600 ÷ 12 = 50.
- Add these to the loan payment: 900 + 200 + 50 = 1,150.
THE ANSWER1,150 per month before excluded costs.
YOUR TURN
A small check for understanding.
What principal results from a price of 250,000 and a down payment of 50,000?
Reveal the answer
200,000. Subtract the down payment from the home price.
Now try your own numbers.
The mortgage payment includes input guidance and the limits of its supported calculations. Use it alongside the method above.
Open Mortgage payment ↗A note on precision: preserve exact fractions where possible and round numerical results at the end. Found an unclear step? Prepare a correction report.